Milk Yield at Second Milking

How good is your memory? Have you milked many fresh cows for their first three or four milkings? How much milk did you collect at second milkings compared to first milkings?

I milked all the fresh cows for a 800-cow dairy for about eight years. My memory for cows (compared to heifers) is that second milking yields were substantially less than yields at first milking. What, however, does a recent study say?

Study: 39 Holstein cows, milk weights recorded for first 10 milkings. [Kessler, E. C. and Others, "Milk production during the colostral period is not related to the later lactation performance in dairy cows." Journal of Dairy Science 97:2186-2192 April 2014]

• As expected, lots of variation among cows in first milking (colostrum) yields varying from about 2 quarts and 21 quarts (about 46 pounds). Fully 75 percent gave at least 5 quarts.

• The variation in first milking yield for cows second lactation and greater was not related to the amount of time between calving and first milking and was only weakly related to previous lactation performance. 

• Average colostrum (first milking) yield was between 16 and 17 pounds.

• Second milking for cows averaged nearly 14 pounds. Compared to first milking yield that is 82 percent.

Yes, that number at second milking was 82 percent. I fear that my memories from 20 years ago are not very accurate - if I had to make a guess based on my recall I would have come up with 50 percent yield at second milking compared to first.

Could I have a problem with selective memory? I recall very well the cases where the cow gave 20 plus pounds first milking and 10 or less pounds at second milking? All the cows that yielded 3/4 or more of first milking at their second milking all blurred together and I don't really remember them? 

True that these results are based on only 39 cows. However, these data are much more definite than my recall. I will keep watching for another study. 

BTW, the title of the article reflects the study's main findings, milk production during the first 10 days in milk is not a good predictor of later production performance.

To Buy or Not To Buy a Digital Refractometer

Digital refractometers are now available in the price range of $350 to $450 that can be used to assess the quality of colostrum, estimate dry matter content of milk and evaluate blood serum total protein.

A question that came up today is whether or not these digital units are more accurate than the hand-held style analog refractometers. Part of the answer is found in the specifications of the unit that is purchased. The digital units will specify resolution and precision (+/-). 

Another part of the answer when you compare the two styles is whether or not the units are automatically temperature compensated. And, how recently have the the units been calibrated?

Another part of the answer is user-related. All of us that have used the hand-held analog units know the challenge of interpreting where the boundary line crosses the scale divisions. My experience is that blood serum total protein samples have fairly sharp boundary lines, milk samples for dry matter are more fuzzy and colostrum quality sample boundary lines are very fuzzy. 

The values assigned for a sample get more and more subjective as the level of fuzziness goes up. Thus, if more than one person at the dairy is taking readings the potential for variation among persons is much higher with analog units than with digital ones. That is, with a digital unit the readings are more consistent and less dependent on who takes the reading.

Maybe the more important question is how accurate do we need to be when using the information to make on-farm decisions? Is a difference of 0.1 in a blood serum total protein reading going to change the decisions we make in colostrum management? When we assess dry matter content of milk how large a difference from our target value do we need to have in order to add  milk powder? If our Brix target for colostrum is 22 are we willing to live with values that are accurate plus/minus 1.0?

My opinion is that whether or not to purchase the multi-scale digital unit is mostly a matter of convenience rather than either accuracy or consistency. One unit is used regardless of the medium to be evaluated. Plus, as a guy I enjoy having high tech stuff around.

You Cannot Bleach Your Way to Clean

I just had yet another question about the concentration of a chlorine bleach solution to use soaking calf feeding equipment. The assumption is that if the one uses the proper concentration of the active ingredient somehow the tube feeders and bottles will become clean. All the bacteria will be gone. 

WRONG!

There are two resources at www.calffacts.com that shed light on this issue. The first is "Bleach is Not Enough to Kill Bacteria" - click HERE to access the text. This note explains why bleach is ineffective in situations where there is significant biofilm accumulation.

The second is "Biofilms Threaten Calf Health" - click Biofilms to access the text. This note includes the topics

• What are biofilms 
• Why are they a threat to calf health 
•  How do biofilms get started 
•  How do biofilms grow 
•  What can we do about biofilms

So, the bottomline? Soaking equipment in a bleach solution when there are biofilms present is simply an exercise - you are not killing the bacteria.

Gizmos or Guesses

That is the title of a presentation by Steve Hayes on managing calves for success. 

Here is the place to click to access this paper. 

In this presentation Steve highlights the use of "gizmos" (tools) to promote better calf management. It is a quick read, his points are well organized. You might even what to print a copy so you can read it two or more times. 

Enjoy. 

The Day After a Holiday

Depending on who you have filling in for you on Friday, 4th of July, sometimes it's frustrating to come back after having a day off from calf care. 

The case in this note is one that may not be too uncommon. On this dairy the calf feeding routine is to begin by walking calves and, in the summer, dumping water pails hanging on the fences in front of the hutches. As you  walk along in front of the older calves none of the calves over five weeks old have any water left. Well, you need to be sure to feed water three times today to help these older calves catch up on their water intake. 

As you get closer and closer to the youngest calves the calf starter grain pails seem rather full. Yes, it happened yet again. The person filling in for the holiday did not really get the message about how much grain to feed calves. He (she) just put five-plus quarts of grain in every pail - youngest to oldest. Since the farm protocol for grain feeding is to feed grain to appetite (nearly empty every morning) this means a lot of work dumping over-filled grain pails. 

Now we are ready to mix the milk replacer. We mix in 30-gallon Brute-brand waste containers. As you set these down off the rack along the wall they don't look "right." A quick check reveals slick, slippery surfaces inside all three containers - oops, they were "washed" by spraying them out with water from a hose and set up to drain. Since the farm cleaning protocol is a 4-step procedure (rinse, wash, rinse, dry) this means washing all this equipment before you start to mix milk replacer this morning. For a review of this protocol and the protocol itself click Washing Checklist or Washing Protocol.

These slip ups just remind us of the need to train and retrain our substitute workers. Since learning-by-doing is an exceptionally effective method of training the ideal to work toward is having the substitute worker shadow or help during a feeding when every possible. For a short checklist on skill-focused training click Here.

She Didn't Test Positive

We were checking for Giardia, a parasite. The test is run on feces. We are looking for parasite cysts.

We checked the feces from the suspect animal. No cysts to be seen. She did not test positive. Conclusion: She does not have giardiasis.

Wrong conclusion!

When testing for an intestinal parasite like Giardia we have to remember that it is normal for shedding to be intermittent. The rule of thumb that work from is to collect fecal samples from a least three different days from the suspect animal. 

Usually the reason we are collecting fecal samples from this calf is that her feces are consistently looser than we expect and she is not thrifty in spite of eating well. At the same time we are checking for giardia we can also look for other parasite evidence from both cryptosporidia and coccidia.

It is not uncommon to find evidence of all three parasites in the same fecal samples. 

Getting Facilities Ready for the Next Crop of Calves

The dairy has a relatively new calf barn. It is set up with six bays with each bay holding a row of calves on each side and work alley in the middle. Each bay is mechanically ventilated with automatic controls for both inlet and exhaust air.

Each bay is run as an all-in, all-out facility. After the calves leave a bay is it is cleaned and sits empty for up to a week before being repopulated. 

The past cleaning procedures include removing all the calf pens and feeding equipment, physically removing all the bedding and manure and pressure washing the walls and floor. The calf pens are pressure washed as well. Feeding equipment is scrubbed and allowed to dry.

I was asked to evaluate this cleaning protocol. While on-site I asked to look at the pressure washer. It is a cold-water unit. I know that high temperature high-pressure water will kill parasites (e.g., cryptosporidia, coccidia, giardia). So, my first recommendation was to switch from a cold-water to a high-temperature-water pressure washer - that is the kind with a boiler that delivers about 180F water. The idea is to cook the parasite eggs as well as wash away all kinds of pathogens. 

I asked about the disinfectant that was used after a bay was cleaned. "Nope, we don't use a disinfectant," was the reply. They have available both Virkon-S and Tek-Trol from a local supplier. Both of these would be effective as a follow up to the pressure washing. I have been trying chlorine dioxide in the past year. Click Here for a resource on chlorine dioxide we are using at our vet clinic. The commercial product Oxine is available as well (http://www.bio-cide.com/).

The rationale for following up the pressure washing with a disinfectant is that no matter how carefully one pressure washes there are some residual pathogens that remain on walls and floors. 

In summary, the idea is to get rid of manure - you cannot disinfect manure. Then, pressure wash to remove as much organic matter as practical. Then, disinfect as a final step to sweep up the "escapees." Letting the facility sit as long as possible before repopulating is a best management practice.